Conservation and management of energy are very essential to our country especially in the industrial sector because of huge amount and high quality energy used in this sector. Further, the cost of energy can be significant in relation to over all production costs.
Energy use is treated not as a necessary overhead, but as a variable cost which can be controlled in the same way that labour and materials are. Therefore, appropriate conservation and good energy management is the cheapest, safest, fastest and most economical way of “producing” energy. The basic tool needed to control industrial energy costs and the management of the energy is a on-line energy monitoring system which provides vital information on energy usage, pattern of energy usage and specific energy consumption in an industry. The present invention is directed towards achieving the above said needs.
A Paper titled “Energy Conservation through Management” by Michael R. Boddington in Productivity, Vol.32, No.4, January–March 1992, 617–624 describes a management approach for saving energy through the systematic approach of monitoring and target setting (M&T). M&T is a management information and cost control system which is the key to reducing energy consumption and cost. This systematic approach will enable industries to reduce the energy consumption, control costs with minimum of resources and efforts and increase profits.
The paper describes the basis of M&T System and how to set it up in a manufacturing organization. It describes clearly how to set up account centers, making people responsible, collecting and analyzing the data and computerizing. The following steps are required in setting up an M&T system:    1. The Audit    2. Selecting the Energy Account Centres (EACs)    3. Deciding on metering requirements    4. Formulating an effective management structure    5. Setting-up a data collection system    6. Setting standards    7. Setting targets    8. Reporting
The Audit: Before setting up an M&T system an energy audit and site survey is recommended with the following aims:                To obtain information on energy consumption and energy costs over the preceding 1 or 2 years broken down according to the energy source.        To estimate how much energy is used in different applications, i.e., process, space heating/air conditioning.        To identify the opportunities for energy saving and the measures which could be taken to improve energy efficiency.        To estimate the cost of implementing these measures and the potential savings.        
Energy Account Centres (EACs): The number and locatins of EACs will depend on the annual energy consumption and the nature of manufacturing processes. At a small factory the energy consumption of the whole site may be monitored through a single EAC. At larger sites EACs will correnspond with the main stages of areas of production so that the management is made directly accountable for the efficient use of energy. In deciding on the location of an EAC it is necessary to consider the following:                Whether the estimated energy consumption and the potential cost savings would justify the cost of metering and the effort involved in metering.        Whether energy used can be satisfactorily related to throughput and that practical standards can be set.        
Metering: In order to first draw a layout of the site, noting existing meter positions in relation to the proposed EACs. It will then become apparent where additional meters need to be installed.
Management Structure: It is important to get the management structure right, a typical energy management team for a manufacturing organization would be as follow:                General Manager—who would be the chairman or the energy executive and would ensure commitment from the top.        Energy Manager—a senior manager who would manage and co-ordinate energy use on the site, advise on policy, formulate strategy and implement programs.        Production Manager—involvement and commitment from the users are important.        Management Accountant—the M&T system should be integrated with the standard company accounting procedures.        Services Superintendent—person responsible for supplying the sites energy services.        Maintenance Manager—maintenance plays a key part in keeping plant operating to its optimum efficiency levels.        
Data Collection: The essential steps in setting up a data collection system would be:                Collect Energy and Production Data: The production data should have a direct relationship with the energy consumed and in the case of space heating or air conditioning should be related to heating or cooling degree days respectively.        Prepare log sheets: The log sheets should be kept simple, it is only a means of transferring meter readings and production data into the computer.        Identify Staff Responsible: A person within such an EAC should be given the task of reading the meters. This can be easily accomplished as part of the employees' existing job description. Training should be given where appropriate. Production departments should supply this appropriate data.        
Determining Standards: There are obvious ways in which the data can be interpreted but ultimately there will always be a relationship between the specific variables. The type of standard equation suitable for an EAC will depend on the number of specific variables and the form of relationship between energy and these specific variables.                Type 1: E=a                    Energy consumption E is constant a and there are no specific variables for the EAC. In some cases the energy consumption of an EAC may initially appear to be constant, but after the introduction M&T and improved control, a dependence on a variable may become apparent. A standard of this type may also be set when a very limited range of data is available for an EAC possibly due to an almost constant level of production.            Obviously, the standard in this case is the average energy consumption (per day, week, etc.) calculated from the historical data available.                        Type 2: E=a+bP                    Energy consumption is dependent on one specific variable (P) and the relationship is that of a simple straight line. For this type of equation the constant, a, is the energy consumption that occurs when the value of the specific variable is zero and is called the intercept. The constant, b, is the increase in energy for each unit increase in the value of the specific variable and is called the slope of the line.            This type of standard equation may occur for a wide range of EACs, for example a simple process area where P is production throughput or a space heating area where P is degree days.            The standard equation is derived by statistical analysis of the historical data using the least squares fit method. Manual calculation is not recommended and access to a suitable programmable calculator or microcomputer should always be sought.                        
Setting Targets: Two principle methods of target setting are available. They are:    (a) Based on Previous Performance: When analyzing data to a set standard equation a degree of scatter is normally expected. In other words a range of performance has occurred. It can be argued that it ought to be possible to repeat the best levels of performance observed. In this way a target can be set at a level which has already been achieved on location and is therefore realistic.            If a standard line has been drawn through a set of data, the points below the line can be identified as those with the best performance. A new line of the same type can be drawn through these points to become the target line. This can be performed automatically using computer software. Ideally the target line should be based on 10 to 20 data points. When a computer is being used for the analysis, this method offers a simple means of setting realistic targets.            (b) Simple Percentage Reductions: Using this method a target can be set simply by aiming at say a 5% reduction in energy use relative to the standard calculation, this could be appropriate where the target produced by the previous method was found to be unsuitable.
Reporting: The report should contain the values of the energies consumed, variables, specific energy ratios of actual, standard and target, percentage energy cost and cost variance from standard as well as target.
Conclusion: Monitoring and targeting has proved to be a very cost effective way of reducing energy costs and more importantly sustaining the initial savings made. Computerising the M&T process will speed up and simplify the whole process of this management information system.
Another paper titled “A Microcomputer-based Energy Monitoring Program for Industry (EMOPIN)” by Z. Z. Yu, S. N. Tay and W.G. Cartwright Computers in Industry 13 (1989) 155–167 introduces a microcomputer-based energy monitoring program for industry (EMOPIN). The essential information of energy consumption in industrial plants is discussed and analyzed. For running the program, the energy consumption data, the production output data, and other relevant information are to be fed manually into a database. The program processes this information into useful and meaningful indicators such as Specific Energy Consumptions (SECs) and Energy Cost Factors (ECFs) and provides reports to the plant's energy managers or engineers. Where appropriate, suggestions are provided to assist in the identification of the source of any energy consumption abnormality.
In this paper, a special treatment have been given for deriving the Specific Energy Consumption and the gist is as given below.
Energy consumption should not be expected to be directly proportional to production output and some special indicators for energy management should be introduced to provide useful and meaningful information. Specific energy consumption (SEC) is selected as one of the indicators. It is normally defined as the energy consumption per unit production output. As a general rule, the value of SEC reduces as the rate of production increases due to the effect of economies of scale.
In manufacturing industries, it is often found that a variety of products of a similar nature are produced, and at the same time various types of energy are consumed in the production processes. The measurable quantities are (a) the consumption of each energy type over a period and (b) the output of each product type over the same period. In the simplest case, the different products may be produced totally independent of each other. Alternatively, they may share the same production facilities with other products. In a fully automated production process, it may be possible to meter the separate energy inputs to each product regardless of whether they use shared equipment or not and then to obtain SEC for each product under each energy item. In practice, it may be difficult, or even impossible to obtain such detailed information on different energy inputs to each product. Two methods are introduced to solve this problem.
The first method is to convert the output of each product into the equivalent output of a standard product and then get the specific energy consumption under each particular energy item (SEC). The governing equation of the first method is as shown below:
  SEC  =            (              Consumption        ⁢                                  ⁢        of        ⁢                                  ⁢        a        ⁢                                  ⁢        particular        ⁢                                  ⁢        energy        ⁢                                  ⁢        item            )              (              Total        ⁢                                  ⁢        equivalent        ⁢                                  ⁢        production        ⁢                                  ⁢        output            )      The numerator of the equation is the consumption of a single energy type, such as electricity, in the production processes which can be obtained from main meters. The denominator of the equation is equal to the sum of the actual output of each product times its equivalent factor (EF). One product will be selected as the standard product having an equivalent factor of 1.0. This may be the product which normally has the greatest output. The equivalent factor of all other products may then be determined on the basis of their value relative to the standard product. In this report, however, the equivalent factor is determined on the basis of the energy input to a product in relation to the energy input to the standard product.
The second method is to convert the consumption value of each energy item into an equivalent energy value and get the specific energy consumption for a particular product (SEC_1). The specific energy consumption for a particular product (SEC_1) is defined as:
      SEC_    ⁢    1    =            (              Total        ⁢                                  ⁢        equivalent        ⁢                                  ⁢        energy        ⁢                                  ⁢        consumption            )              (              output        ⁢                                  ⁢        of        ⁢                                  ⁢        a        ⁢                                  ⁢        particular        ⁢                                  ⁢        product            )      The numerator is the sum of each fuel type used for a particular product, each multiplied by an equivalent energy content factor. This factor represents the total energy of a fuel. The equivalent energy content factors of common industrial energy items are well known. This permits the exact definition of equivalent factor of different products on an energy input basis.
The equivalent factor (EF), can then be defined as:
  EF  =            (              SEC_        ⁢        1        ⁢                                  ⁢        of        ⁢                                  ⁢        the        ⁢                                  ⁢        particular        ⁢                                  ⁢        product            )              (              SEC_        ⁢        1        ⁢                                  ⁢        of        ⁢                                  ⁢        the        ⁢                                  ⁢        standard        ⁢                                  ⁢        product            )      In theory, the second method is better than the first method. But in practice, the first method is more acceptable and practicable in manufacturing plants.
EMOPIN program has been demonstrated to process three months daily data of a beverage manufacturing plant in Singapore. The company manufactures six different type of products, viz., BOTTLE, CAN, PET, HANDY, CONC AND JUICE. The types of energy sources used are electricity, fuel and water. The daily input raw data are processed into useful information such as daily SEC, daily ECF, and their deviations from the standard SEC and ECF, etc.
This daily report gives the details of product and energy separately. In the product information, it gives the quantities of each type of product along with value, net output and equivalent factor. The net consumptions of all types of energies are given in the energy information along with cost incurred on each type of energy, actual specific energy consumption, standard specific energy consumption and the percentage deviation. At the end of report, some useful hints are generated by the program to draw immediate attention of the management for corrective actions. A typical example of the report generated by this system is shown in FIG. 10.
Enercon Systems, Pvt. Ltd. Bangalore, India is one of the pioneers in manufacturing digital energy meters and energy management software products. The company designs, manufactures and markets a wide range of Digital panel meters, electronic energy meters and multi-function load managers.
The company is supplying eLAN Energy Management Networks which consist of Enercon electronic energy meters or multi-function meters connected to PC on MODBUS. The block diagram of the eLAN Energy Management Networks is shown in FIG. 8. An eLAN SCADA software runs on a PC and supports all standard features required for an Electrical Energy Management System. It generates different types of energy information reports with pre-configured screens of mimics, trends, history, alarms etc.
Alacrity Electronics Limited, Chennai, India is supplying KRYKARD PC based Energy Monitoring network, which uses its microprocessor based panel meters and AlEnSoft software for industrial on-line electrical information for effective analysis and reporting. The block diagram is shown in FIG. 9. Alabar Associates, England is manufacturing Albar Windows Energy Monitoring System. It consists of multiple data loggers connected to PC over RS-485 communication interface. The system can be used to monitor and record electricity, gas, steam and other meters. It can take care of cost centers within sites and even for widespread sites. Receives information in the form of pulses and is optimized for meter data services market.
Drawbacks and Difficulties in the Existing Known Art
The methodology for industrial energy management has been thoroughly worked out in the above referred existing literature. Even some companies are trying to implement this methodology and supplying the systems. However these systems are not very appropriate for comprehensive industrial energy management. They give only partial solutions.
Most of the companies are supplying energy monitoring systems as an extension of their metering product range. The solution involves some difficulties like introducing these meters into the control panels which warrants additional work for installation. As the systems are extensions of metering products, the cost is not optimized. System flexibility is needed to optimize the cost.
Requirements of Removing the Drawbacks
At present, there are many industrial electrical distribution systems where a single utility meter is provided at an electrical service entrance exclusively for electrical tariff payment purposes. With this arrangement, individual energy consumptions in different utilities and production units in an industry cannot be individually monitored and cost allocated. This tends to promote waste as the information on what energy consumption should be and what it is not available preempting all efforts for energy conservation. Similar is the case for steam flow to different sections of the industry.
It is well known now that Energy Monitoring System is a basic tool for industrial energy management. Different types of measurements are needed for energy management, like temperature, pressure, flow, time etc. Energy Monitoring systems should have the flexibility to monitor these parameters along with electrical energy. Cost is one of the impediments for the proliferation of industrial energy monitoring systems. To keep the cost at moderate level, sometimes indirect measurements are helpful. For example, it is possible to derive the energy consumption of a constant load by noting its time of operation.
At present industries are evaluating the energy monitoring systems in terms of financial benefits and payback periods. Hence relevant energy studies are necessary for optimum configuration of energy monitoring systems. Hence industrial energy monitoring should be seen more as an evolving of solution which involves energy studies, system configuration, system development, system integration, commissioning, installation and training.
Due to the absence of a system to determine the above information there is quire a lot of wastage of valuable energy resulting in many problems such as higher production cost, environmental pollution due to higher energy consumption etc.
Objects of the present Invention:
The main objective of the present invention is to provide a computer controlled on-line Energy Monitoring System which is relatively simple, reliable and utilizes low-cost data communication system for conservation and good management of energy.
Another objective of the present invention is to provide a computer controlled on-line Energy Monitoring System which is flexible and versatile, and which can be easily adapted to accurately take various measurements from industrial electrical consuming equipment and standard industrial transmitters which may be connected to different channels of the remote data acquisition systems.
Still another objective of the present invention is to provide a computer controlled on-line Energy Monitoring System by which the industry personnel can work out the schedule of maintenance of the equipments by using the data generated by the system. Yet an additional objective of the present invention is to provide a centralized energy monitoring system which facilitates energy monitoring of measurements connected with electrical energy as well as thermal energy.
One more objective of the present invention is to provide a system which will indicate the changes in the pattern of daily energy consumption of a particular machinery using which prompt and appropriate maintenance decisions for optimizing the operational and maintenance costs can be initiated.
One another objective of the present invention is to provide a low cost energy monitoring and accounting system which takes care of both electrical and thermal energies.
Still another objective of the present invention is to provide a data acquisition system useful for incorporation in the energy monitoring of the present invention